sh: Add imv to iv image alias

sh/.config/sh/alias

@@ -94,8 +94,18 @@ if exist vifm; then
     alias vmm='vifm ${PWD}'
 fi
 
-# nsxiv image viewer
-if exist nsxiv; then
+# default image viewer
+if exist imv-folder; then
+    iv() {
+        if [ "$#" -eq 1 ] && [ -f "$1" ]; then
+            imv-folder "$1"
+        else
+            imv "$@"
+        fi
+    }
+elif exist imv; then
+    alias iv=imv
+elif exist nsxiv; then
     if exist nsxiv-rifle; then
         alias iv=nsxiv-rifle
     else